DIY options for Chinese electret condensers?

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Icantthinkofaname

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I have one of those Chinese electret condensers sitting around, the ones that go for like $20 on Amazon, and I think doing a DIY project with it might be interesting. I'd like to put the mic to use in some way rather than just throwing it away.

Ideally I'd like to be able to just replace the capsule if it's possible to get decent results with only a capsule swap. I see some decent looking electret capsules on JLI Electronics like the TSB capsules, but I don't know if those are any good (the frequency response looks alright at least).

I don't have any experience with designing or modifying electronics so I don't know how to design a PCB or read a schematic diagram of circuitry which is why a capsule swap is preferable. No idea how to polarize a capsule or design a circuit for that so large diaphragm (32mm/34mm) capsules are out of the question.

If a replacement circuit board is necessary are there any decent cheaper ones? I know Microphone-Parts has a $100 PCB kit, but if I buy that circuit board and their offered TSB capsule I think I might as well just look at used microphones. Links to guides and already completed projects with instructions using those throw away mics (BM-700/800 and the like) are welcome as well as are links to parts.

I do have a very usable LDC (U87 style mic, but transformerless and not very harsh sounding) so this is really only a project or mic for occasional use, not quite sure what I want tone wise but maybe a flat-ish or dark sound would be good for contrast with the accented mids and highs that my current mic has?
 
The thing is the mic parts kit is it’s a great way to get started, about the easiest way to paint by the numbers and support if something goes wrong,  and the leaning process gets started.  Understanding schematics, layouts, and how to make prototype pcb’s is like learning to read for the first time, a new world opens up to you.  Especially if you get a taste for some of the great vintage circuits that are rare as hens teeth.
if you are looking for the cheapest way, diy is not it, it’s a money pit, great fun, lots of learning,    and the sheer joy of saying I built that. 
With low cost China labor , you can get some pretty good deals if you goal is saving money.

Just my opinion.

 
chipss36 said:
The thing is the mic parts kit is it’s a great way to get started, about the easiest way to paint by the numbers and support if something goes wrong,  and the leaning process gets started.  Understanding schematics, layouts, and how to make prototype pcb’s is like learning to read for the first time, a new world opens up to you.  Especially if you get a taste for some of the great vintage circuits that are rare as hens teeth.
if you are looking for the cheapest way, diy is not it, it’s a money pit, great fun, lots of learning,    and the sheer joy of saying I built that. 
With low cost China labor , you can get some pretty good deals if you goal is saving money.

Just my opinion.
Maybe I'll wait a bit and look into the kit later then.
 
Microphone parts has a capsule replacement:
TSB-2555B Electret Capsule

Sounds like an upgrade, but I've never used one.
According to AudioImprov, the basic circuit is noisy:
Testing revealed that performance wasn’t too bad except for a lot of noise which turned out to come from the voltage regulator. Adding an R-C filter between the regulator transistor Q6 and the input stages helped a lot. That might be all you’d need to do if you’re upgrading to a better electret capsule like a Primo, a JLI TSB2555B, or a Mic-Parts RK-99.
I'd be interested in knowing how you proceed. I bought a couple of these for donor body parts. The PC boards are sitting there looking at me :) Must resist.
Here's the url:
http://audioimprov.com/AudioImprov/Mics/Entries/2015/12/20_Modding_a_BM-800_Mic.html
 
12strings2hands said:
Microphone parts has a capsule replacement:
TSB-2555B Electret Capsule

Sounds like an upgrade, but I've never used one.
According to AudioImprov, the basic circuit is noisy:
Testing revealed that performance wasn’t too bad except for a lot of noise which turned out to come from the voltage regulator. Adding an R-C filter between the regulator transistor Q6 and the input stages helped a lot. That might be all you’d need to do if you’re upgrading to a better electret capsule like a Primo, a JLI TSB2555B, or a Mic-Parts RK-99.
I'd be interested in knowing how you proceed. I bought a couple of these for donor body parts. The PC boards are sitting there looking at me :) Must resist.
Here's the url:
http://audioimprov.com/AudioImprov/Mics/Entries/2015/12/20_Modding_a_BM-800_Mic.html
Yeah I was looking at that capsule (or the other similar JLI one) since you can get it directly from JLI for $13. It's really just a project to see if I can make something with a tone different from my Black CM1 mic which is bright, and to my understanding that capsule is considerably less bright since Mic Parts seems to say it's somewhat U47 like. Of course if I need to replace the circuitry as well I'll just end up looking at used darker sounding mics.
 
I can recommend  the TSB 2555 capsule. I have used them in BM700 bodies, as well as in my own homemade mic bodies, and they are a very nice capsule, giving clean reproduction and able to take quite loud sound sources. If you use these capsules, you will not be disappointed. And they also seem very close in specs, so it is easy to make a very good pair of mics with very little variation where a mic pair is needed in recording. If using them for voice, I recommend a pop filter.
Kindest regards,
zephyrmic
 
The only problem I have had with them, is that they are sometimes not properly sealed.
I have had a few that spontaneously fell apart...  :-[
Later, as a precaution, I glued the back of the capsule to the surrounding rim.
 
> a better electret capsule like a Primo

Off-topic, but I will stick this in:

Primo ad from 1965:
 

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How about the Rayking capsules like this one:

https://www.alibaba.com/product-detail/-47dB-ECM-electret-condenser-microphone_60444754626.html
 
mhelin said:
How about the Rayking capsules like this one:

https://www.alibaba.com/product-detail/-47dB-ECM-electret-condenser-microphone_60444754626.html
You can get Transound's capsules for like $15 so I'd just go with that over the Rayking, if only because they're better known and people have a lot of experience with them.
 
Meteor has opamp (MAX4475) impedance converter, don't know how much it affects to (degrades) the sound quality.

https://www.youtube.com/watch?v=NrQkHgvNNjY

The repair looks bad, he got wrong opamp MAX4477 (dual) instead of MAX4475 (or MAX4488). In the end you can hear the sound little, not bad compared to the capsule in BM800, level is quite low.

Here is another Rayking, BU2578L-383 (previous was BU2564L-423) :
https://www.alibaba.com/product-detail/ORIGINAL-Manufacture-Capsule-Mic-Electret-Condenser_60460958214.html

... and third,  BU2670L-423, but it's got internal FET:
https://www.alibaba.com/product-detail/26mm-big-size-uni-directional-electret_60530215805.html
 
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